Conventionally, there has been studied to blend a softening agent to a detergent for the purpose of preventing the loss of softness to have a stiff feel of the washed fibrous manufactured article due to the detachment of a fiber treating agent, deposition of salts or the like. For example, as a softening agent for giving softness to the feel of the fibrous manufactured article by the deposition of the softening agent on the fiber surface, a clay material such as smectite (see, for instance, Patent Publication 1); a cationic surfactant such as a dialkylated quaternary ammonium salt (see, for instance, Non-Patent Publication 1); a silicone such as poly(dimethyl siloxane) (see, for instance, Patent Publication 2); and the like have conventionally been known to be blended. Also, in recent years, studies have been made on a method of enhancing softening effects of a clay mineral from the viewpoint of easiness in formulation, environmental issue and the like. For instance, there have been known a combined use of bentonite and a pentaerythritol compound (see, for instance, Patent Publication 3), a combined use of a clay mineral and an aggregating agent (see, for instance, Patent Publication 4), a combined use of bentonite and a soluble potassium salt (see, for instance, Patent Publication 5, and Non-Patent Publication 1), and the like.
On the other hand, in recent years, as a part of reinforcement of detergency, especially detergency against oil stains, a nonionic surfactant has been formulated as a main surfactant. However, as a result of intensive studies, the present inventors have found a disadvantage that if a nonionic surfactant is present in a detergent containing a clay mineral, the dissolubility of the clay mineral itself is likely to be lowered, which causes the detergent to remain on clothes, thereby causing softening ability of the clothes to be lowered.    Patent Publication 1: JP-A-Showa-49-85102    Patent Publication 2: JP-A-2002-249799    Patent Publication 3: JP-A-Hei-5-140869    Patent Publication 4: JP-A-2002-541342    Patent Publication 5: JP-A-Hei-8-506843    Non-Patent Publication 1: Shuchi Kanyo Gijutsu Shu (Laundry Powder Detergent), published on Mar. 26, 1998